Why a poor sense of smell in old age might be a major warning sign

A study involving thousands of elderly patients found that those lacking a keen sense of smell were seriously at risk of dying sooner than others.

A research team at Michigan State University has suggested that elderly people visiting the doctor for their regular check-up should probably get a smell test while they’re there.

In a study published to the journal Annals of Internal Medicine, the findings showed that older adults who have a poor sense of smell may see an almost 50pc increase in the risk of dying within 10 years, even among healthier individuals.

Using data from the US National Institute on Aging’s Health ABC study, epidemiologist Honglei Chen and his team reviewed information from almost 2,300 participants aged between 71 and 82 years of age over a 13-year period. Including men and women of different ethnicities, the study asked them to complete a smell test of 12 common odours, classifying them as having a good, moderate or poor sense of smell.

Compared with older adults with a good sense of smell, those with a poor sense of smell were found to be at a 46pc higher risk of death at 10 years, followed by 30pc at 13 years. The biggest surprise, according to the team, was that the healthier participants at the start of the study were largely responsible for the higher risk.

While a poor sense of smell is known as an early sign for Parkinson’s disease, dementia and weight gain, these conditions only accounted for 28pc of the increased risk.

“We don’t have a reason for more than 70pc of the increased risk. We need to find out what happened to these individuals,” said Chen, who plans to pursue the mystery in future studies. He did add that a poor sense of smell might be an early, sensitive sign for deteriorating health that other tests wouldn’t pick up.

“It tells us that in older adults, impaired sense of smell has broader implications of health beyond what we have already known,” Chen said. “Incorporating a sense-of-smell screening in routine doctor visits might be a good idea at some point.”